ESP firmware:
- Store HMAC key in NVS via Preferences library instead of compile-time
hmac_key.h
- KEY? responds with HMAC_KEY:<hex> (if provisioned) or NO_KEY
- New SET_KEY:<64-hex> command stores key in NVS and responds OK
- Boot messages updated to reflect provisioning state
Android app:
- UsbKeyReceiver detects NO_KEY response and auto-provisions:
generates random 32-byte key via SecureRandom, sends SET_KEY,
waits for OK, saves key to SharedPreferences
- Read loop now breaks on both HMAC_KEY: and NO_KEY responses
Cleanup:
- Removed tools/generate_hmac_key.py and src/hmac_key.h
- Removed hmac_key.h from .gitignore
- README updated for new provisioning flow
9a84b05b8a